Forming paper from modified calcium alginate fibers



Patented June 17,. 1952 UNITED- STA-T Es PM EINT critics 2,600,504"FORMING PAPER FROMMODIEFIEB GALGIUM- ALGINATE FIBERS rthii'rJii nsoii,needs, amiss (jieer'g'e vii'llatt;

I I t ammates; Lenaomsmena, a r tis company b Drawin enn iea Jun anstsethi ut 31 2 26. In Great Britain June-13 1947 1 2 This inventioncomprises-improvements1hor netiburh with a flame or pro agate ombustion,relating to" themanufacture'of paper. although it may char under heat.Conseq iitly Paper is ordinarily manufactured from the paper made fromfibres of calcium alg'iriate' is various forms of fibrouscellulosic'materials such non infiammable' and if treated with alkalisaswoo'd'pulp; rags, sisal fibres and'the like; The 5 stronger than thatused as'a s' 'e'llin'g agen for fibres are beaten in water to form apulp" and making the papen it caneasily' be wholly the beatinggivesthem' a" quality Of adhesion S0 solved" therein. The" invention is:not H r that when the pulp containingthem is'drained limited to theemployment of eare iu'm' a1 hate on a porous surface the fibres felttogetheiand as-fibr'es of manyetheraninates such' as pte'r becomeacoherent sheet; For' emepu rpose's it a lginate';ziiidalginate,chrqmiiiriial'giiiatab ""3 1 would be advantageous to have soluble"papers. 1mm; a ternate and mahyethers which-are water'- Cellulose fibresare not soluble in water'o'r' weak insoluble" have been: spun. A"suitableageiitjifer acids or alkalisi Papers are made which are anyparticular alginicfibr, will be t e which called soluble butthisorilymeans that they tendst'd dissolve theffibre biit is"ein'ployed-"in a become so soitin water as to be readilydisintestrengthsufficient only; within the time of -trea'tgrated andterevertto the state of pulp Paper merit-employed,toao'tsuperficially'thereoni'so'as moreover-is readily inflammable andfor'many to swell the outer layers. Agents suitable for purposes anon-infiammablepaper would be of trial for this purpose c'aii'be'selectedaccord-ing great advantage. to'the known chemical properties oithe algi- It is an object of the present invention to pronates'. Forexample; copper alginate isfrsp'o'nvidep'a'per which aiiordsthadvantages of semsiv' to ammonium phosphate; c romium algibilityoroiresistance' to fir'e or' both. nateis'resistant to alkalisl' Not allalg'iir'iatesare Accordingtto' the presenrin vention a processnon-inflammable, and if an inflammable algi'nate of productionofpap'enconsists'in'taking"wateris employed of coursethe resultingpaperwill insoluble alginic' fibres, comminu'ting them and 2 partake ofthisproperty. The'a'ctu'al strength making them into a pulp. in water,rendering Of the swelling age'nt in'ani particularcase willthem'adherent so as to" be capable of felting toep l 'poii ajnumbereffactors including the gether' into acoherentsheetby the introduction eera r 'f m (if treatment" and; the into the pulp of'a swelling agentwhich causes ha fi s' 0f Watr? 1 7; An example of the alginicfibrestoswell and become sticky in u c s a fi and lirri s. f t as water,and thenmakingpaper from thepulp so j n f ii U I Qth r- 0 d1- prpareitions a simple preliminarytrialwill sumce to dew t q mm algjnic flBj-egd fiofi' b ecgme termine the best strength to obtain the'desired sesameof felting when beaten lI 1- Watr.-' That sul g is'to say, although amat of such fibres may be T1 fi tl g' fibi' 'es may be produced iromproduced on a screen, it will not holdtogether J Wn aI mw s'o staple fi-cu tins or when drained and dried because there is no tend-Otherwiseency for one fibre to adhere to another. There y yin theconcentration of alkali or oth therefore is a fundamental distinctionbetween Swellmg f b it is possible to control the the process accordingto the present invention 40 amount fb 1ndmg ion which takes place andthe ordinary procedure of paper making, in between i fibres, and thus toy h that the fibres must be brought into a feltable characterlstws ofthe resultant paper. The condition, not by beating but by the additionto quahty 0f e paper may a so be V d y a terthe pulp of a swellingagent-h ing the length of the alginate fibres employed. Fibres ofcalcium alginate are soluble in weak In the absence of an alkali orother swelling alkalis such as a 1% solution of sodium car agent thereis no adhesion between the fibres Of bonate. We have found however thatif asodium the p p and f tOO reat a concentration of carbonate solutionis made sufiiciently weak it alkall is employed, the fibres become tooweak can be used as a swelling agent to swell the outer and swollen E behandled O IVeniently.

surface of calcium alginate fibres without dis- The followmg examplelustrates one applicasolving the fibres, and that this combination oftion of the process: calcium alginate with sodium carbonate used as E Za swelling agent is particularly advantageous for mm? 9 the purpose ofthe present invention. Calcium Calcium alginate fibres, consisting ofwaste alginate is also non-inflammable-that is, it does from theproduction of alginate staple fibres 1'01' use in spinning yarns, weretaken, chopped up fine and dispersed with tap water to form a pulp so asto produce a suspension containing 3 grams of calcium alginate fibre ineach 300 millilitres of water. The water employed had a hardness of 32",that is to say it corresponded to the presence of 32 parts of CaCOs per100,000 of water. 0.2 gram of sodium carbonate was added for each 300millilitres of the above-described algihate-containing pulp, and thepulp was kept stirred at a temperature of ISO-70 F. for 30 minutes. Thequantity of sodium carbonatestated is sufiicient to convert from to ofthe calcium alginate to sodium alginate. Sufiicient 01 this suspensionwas made up to fill a shallow vat, and a sieve covered with a piece ofNo. 1 filter paper was immersed in the suspension so as to be filledwith the pulp, removed with shaking in the usual way to cause the fibresto mat together, drained and the resulting filtered paper wastransferred to a wire gauge drainer and dried thereon, and thenhot-pressed to produce a strong hand-made paper sheet.

In carrying out the process by steps similar to those described in theforegoing example it has been found that 0.4 gram of sodium carbonaterepresents approximately the upper limit of alkali concentration for afibre suspension consisting of 3 grams of calcium alginate fibres in 300millilitres of water. When 0.50 gram were added the fibre became tooswollen to handle and was discarded. 0.40 gram gave a parchmentlikepaper and smaller quantities softer and weaker papers. It is to beexpected that with harder water slightly more sodium carbonate would berequired. This quantity corresponds to the conversion of 50% to 55% ofthe calcium alginate to sodium alginate.

It should be noted that although calcium alginate fibre is a preferredstarting material for the production of these alginate papers, otherfibres made from alkali-soluble, but water-insoluble alginates mayequally well be used. In the example described above, sodium carbonatewas used as the swelling agent. In place of this compound when usingcalcium alginate fibres any of the water-soluble salts of the alkalimetals, or ammonium, or magnesium which yield insoluble calcium saltsmay be used. All that is required of a swelling agent for any waterinfibres, reducing them to the form of a shortfibre aqueous pulp,introducing a soluble alkali salt of an anion which will form aninsoluble salt with the alkaline earth in the insoluble alginate fibres,in suificient quantity to combine with from 15% to of the alkalineearth, thus causing the fibres to swell, and then causing the fibres tofelt together to make paper.

2. A process of making paper which consists in taking water-insolublealkaline-earth alginate fibres, reducing them to the form of ashort-fibre aqueous pulp, introducing sodium carbonate in sufficientquantity to combine with from 15% to 55% of the alkaline earth in thealginate and thus causing the alginic fibres to swell, and then feltingthe fibres together to form paper.

3. A process of making paper which consists in taking calcium alginatefibres, reducing them to the form of a short-fibre aqueous pulp,introducing sodium carbonate in sufiicient quantity to combine with from15% to 55% of the calcium in the alginate and thus causing the alginicfibres to swell, and then felting the fibres together to form paper.

4. A process as claimed in claim 1, wherein the paper after being feltedand drained is hot pressed.

5. A process as claimed in claim 2, wherein the paper after being feltedand drained is hot pressed.

6. A process as claimed in claim 3, wherein the paper after being feltedand drained is hot pressed.

ARTHUR JOHNSON. EDWIN GEORGE MILLATT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 737,421 Krefting Aug. 25, 19081,509,035 Thornley Sept. 16, 1924 1,675,244 Blombery June 26, 1928FOREIGN PATENTS Number Country Date 316,119 Great Britain July 23, 1929492,264 Great Britain Sept. 13, 1938 OTHER REFERENCES Journal of theSociety of Dyers and Colorists, vol. 62, page 100, (1946).

Colloid Chemistry by Alexander, vol. VI, pages 718-722 (1946), publishedby Reinhold Publishing Corp, New York.

1. A PROCESS OF MAKING PAPER WHICH CONSISTS IN TAKING WATER-INSOLUBLEALKALINE-EARTH ALGINATE FIBRES, REDUCING THEM TO THE FORM OF ASHORTFIBRE AQUEOUS PULP, INTRODUCING A SOLUBLE ALKALI SALT OF AN ANIONWHICH WILL FORM AN INSOLUBLE SALT WITH THE ALKALINE EARTH IN THEINSOLUBLE ALGINATE FIBRES, IN SUFFICIENT QUANTITY TO COMBINE WITH FROM15% TO 55% OF THE ALKALINE EARTH, THUS CAUSING THE FIBRES TO SWELL, ANDTHEN CAUSING THE FIBRES TO FELT TOGETHER TO MAKE PAPER.